Drilling attachment

ABSTRACT

A drilling attachment for use in wet and dry drilling operations includes a housing having first and second fluid conduits, and a drive shaft mounted within the housing and having fluid transmitting first and second end portions in fluid communication with a respective first and second fluid conduit. In one embodiment, at any time one end of the drive shaft is coupled to a drive unit and the other end of the drive shaft is coupled to a core drill bit. In a dry drilling operation, dust is extracted from the core of the drill bit, is passed through the drive shaft and exits the housing via one of the fluid conduits. In a wet drilling operation, fluid such as water is passed through the other of the fluid conduits, through the drive shaft and into the core of the drill bit.

The present invention relates to a drill attachment, and in particular,to a drill attachment for use in wet and dry drilling operations.

Drilling bores in walls and the like may be achieved using a suitabledrill bit coupled to a drilling unit such as a domestic hand held drillor an industrial drill, for example. Where small diameter bores arerequired it is usually sufficient to use a solid drill bit. However,where larger diameter bores are required it is conventional to use acore drill bit which consists of a tubular member having a central boreand having cutting elements, such as diamond impregnated segments,mounted at the leading edge thereof.

In order to improve the quality of bores drilled with core drill bits,and to extend the useable life of the cutting elements, it is known toprovide means for extracting the dust which is produced during adrilling operation from the central bore of the core bit. This preventsclogging of the hole being drilled, provides a cleaner workingenvironment, provides additional cooling to the cutting elements, andultimately improves the quality of bores which are produced, requiringlittle or no tidying or “making good”.

Dust extraction, commonly referred to as dry drilling, may be achievedby coupling a vacuum or suction device to a special attachment mountedbetween the drill unit and the core bit. The special attachment allowsfor dust to be extracted from the bore of the core bit, into theadapter, and into a collection bag or the like associated with thevacuum or suction device.

Dust extraction is a practical method of improving drilling capabilitiesand efficiency. However, when drilling operations are required inparticularly hard materials, such as granites, concretes, hardengineering and facing bricks, and clay materials and the like, drydrilling is often inefficient and in extreme cases, unachievable. Insuch situations it is known to inject a lubricating drilling fluid, suchas water, into the area of drilling, a procedure commonly referred to aswet drilling. This reduces friction between the cutting elements and thematerial being drilled, cools the cutting elements and assists incontrolling the drilling dust, which is forced out of the hole whendrilling.

Wet drilling may be accomplished by placing a wet drilling attachmentbetween the drill unit and the core bit, said wet drilling attachmentbeing coupled to a fluid supply which passes through said unit and intothe bore of the core drill bit.

A number of problems exist in currently known dry and wet drillingprocedures. For example, each type of drilling generally requires aseparate attachment to be coupled between the drilling unit and the corebit, which requires extra equipment to be stored and easily accessed onsite. Furthermore, attachments which are capable for use in both dry andwet drilling operations are frequently limited in the maximum core bitdiameter with which they may be used, particularly for wet drilling.

Additionally, current systems which utilise a combined dry and wetattachment are prone to clogging, as dust trapped therein from use in adry drilling operation may become saturated during wet drilling if theunit is not properly cleaned after each type of use.

It is an object of at least one aspect of the present invention toobviate, or at least mitigate, the aforementioned problems in the priorart.

According to a first aspect of the present invention, there is provideda drill attachment for coupling a tubular cutting member having a boreto drive means for rotating the cutting member, the drill attachmentcomprising:

a housing defining first and second fluid conduits; and

a drive shaft rotatably mounted within the housing and having fluidtransmitting first and second end portions in fluid communication withthe respective first and second fluid conduits, the first end portionbeing adapted for coupling to one of a tubular cutting member and adrive means and the second end portion being adapted for coupling to theother of the tubular cutting member and the drive means.

Preferably, at least one of said first and second end portions of thedrive shaft is adapted for coupling to a tubular cutting member when drydrilling is required. Additionally, preferably at least one of saidfirst and second end portions of the drive shaft is adapted for couplingto a tubular cutting member when wet drilling is required.

In a preferred embodiment of the present invention, one of said firstand second end portions of the drive shaft is adapted for coupling to atubular cutting member when dry drilling is required, and the other ofsaid first and second end portions is adapted for coupling to a tubularcutting member when wet drilling is required.

Dry drilling, as noted herein, involves extracting dust produced duringa drilling operation from the bore of the cutting member. Wet drilling,on the other hand, involves feeding a drilling fluid, such as water,into the bore of a tubular cutting member during drilling, whichlubricates the material being drilled and cools the cutting member,improving drilling efficiency and increasing the useable life of thecutting member.

Conveniently, at least one of said first and second end portions of thedrive shaft is adapted for transmitting dust extracted from the bore ofa tubular cutting member, and at least one of said first and second endportions of the drive shaft is adapted for transmitting an appropriatedrilling fluid such as water to the bore of a tubular cutting member.

Preferably, one of said first and second fluid transmitting end portionsof the drive shaft is adapted for transmitting dust extracted from thebore of a tubular cutting member, and the other of said first and secondend portions of the drive shaft is adapted for transmitting water orother appropriate drilling fluid to the bore of a tubular cuttingmember.

Conveniently, when dry drilling is required, a suction device, such as avacuum pump or domestic or industrial vacuum cleaner, is coupled to oneof the first and second fluid conduits in the housing. Alternatively,when wet drilling is required, a drilling fluid supply, such as a watersupply is coupled to one of the fluid conduits in the housing. Thedrilling fluid may be pumped from a fluid reservoir or alternatively maybe tapped from a mains supply.

Preferably, one of said first and second fluid conduits is adapted forcoupling to a suction device or the like, and the other of said firstand second fluid conduits is adapted for coupling to a fluid supply.

A suction device or a fluid supply or the like may be coupled to therequired fluid conduit via an appropriate extraction or supply hose.Said supply or extraction hose may be connected to the first or secondfluid conduit using a threaded connection or a jubilee clip or othersuitable adjustable hose clip. Alternatively, any hose may be connectedto the first or second fluid conduit by way of a nipple and slidingcollar arrangement or other quick connect coupling. It should be notedthat any connecting means may be used as would readily be selected by aperson of skill in the art.

Thus, if dry drilling is required, a tubular cutting member is coupledto the end portion of the drive shaft adapted for transmitting dust fromthe bore of the tubular cutting member, the drive means is coupled tothe other end portion thereof, and a vacuum pump or the like isconnected to the first or second fluid conduit in fluid communicationwith the end portion of the drive shaft to which the cutting member iscoupled. On the other hand, for wet drilling, the tubular cutting memberand the drive means are coupled to the opposite end portions of thedrive shaft from that required for dry drilling, and a drilling fluidsupply is connected to the fluid conduit in fluid communication with theend portion of the drive shaft to which the cutting member is coupled.That is, the tubular cutting member is coupled to the end of the driveshaft adapted for transmitting an appropriate drilling fluid, and thedrive means is coupled to the other end thereof.

Preferably, the drive shaft is bearing mounted within the housing of thedrill attachment. Preferably also, the drive shaft is retained withinsaid housing using circlips, for example. However, it should be notedthat any means of retaining the drive shaft within the housing may beused as would readily be selected by a person of skill in the art.

Preferably, the drive shaft comprises a first axial bore which extendspartially through the drive shaft from the first fluid transmitting endportion thereof, and terminates at a point within the drive shaft.Conveniently, the drive shaft comprises at least one radial bore whichextends from the outer surface of the drive shaft and merges with saidfirst axial bore. Preferably, said at least one radial bore merges withthe first axial bore in the region of the terminating end of said firstaxial bore.

Advantageously, two radial bores are provided and are preferablydiametrically aligned such that a first diametric bore is defined whichextends through the drive shaft in a direction normal to the axialdirection of the drive shaft.

Similarly, the drive shaft preferably comprises a second axial borewhich extends partially through the drive shaft from the second fluidtransmitting end portion thereof; and terminates at a point within thedrive shaft. Preferably, the drive shaft further comprises at least oneradial bore which extends from the outer surface of the drive shaft andmerges with said second axial bore. Preferably, said at least one axialbore merges with the second axial bore in the region of the terminatingend of said second axial bore.

Conveniently, two radial bores are provided and are preferablydiametrically aligned such that a second diametric bore is defined whichextends through the drive shaft in a direction normal to the axialdirection of the drive shaft.

Preferably, the location of said radial bores along the length of thedrive shaft is such that said bores are substantially aligned with arespective first and second fluid conduit in the housing. Thus, saidfirst and second axial bores and respective radial bores permit fluidcommunication between the first end portion of the drive shaft and thefirst fluid conduit in the housing, and between the second end portionof the drive shaft and the second fluid conduit in the housing.

In a preferred embodiment of the present invention, one of said firstand second axial bores and associated at least one radial bore in thedrive shaft is adapted for transmitting dust from the bore of a cuttingmember to the respective fluid conduit in the housing. Preferably, theother of said first and second axial bores and associated at least oneradial bore is adapted for transmitting a suitable drilling fluid fromthe respective fluid conduit in the housing to the bore of a cuttingmember.

Conveniently, the drive shaft comprises fluid seals located on either ofthe at least one radial bore through which drilling fluid may besupplied in order to prevent leakage of said drilling fluid.

Advantageously, one end of a tubular cutting member for use with thedrill attachment comprises coupling means for coupling to the driveshaft, and another opposite end of the tubular cutting member comprisescutting elements for effecting drilling.

Preferably, the coupling means includes threaded coupling means,wherein, for example, the tubular cutting member may comprise a malethreaded portion which is received within a female threaded portionprovided on an end portion of the drive shaft. Alternatively, thecutting member may comprise a female threaded portion which receives amale threaded portion provided at an end portion of the drive shaft.

In a preferred embodiment, the drive shaft comprises means forpreventing rotation within the housing when a tubular cutting member iscoupled thereto using a threaded connection. Such rotation preventionmeans may be in the form of diametrically opposed land portions locatedat at least one end portion of the drive shaft, said land portionsproviding gripping means for a tool to restrain the drive shaft fromrotational motion. The land portions may be adapted to be gripped by anopen mouthed wrench or an adjustable pipe wrench, or the like.

Preferably also, the coupling means of the tubular cutting member isprovided on a shank portion associated therewith. The shank portion maybe formed integrally with the cutting member or may be independentlycoupled thereto, as discussed in more detail below.

The shank portion preferably includes a throughbore, permitting fluidtransmission between the bore of the cutting member and one of the firstand second fluid conduits in the housing when in use. Preferably, thearrangement is such that fluid transfer is possible through thethroughbore in the shank portion, through one of the first and secondaxial bores and through a respective at least one radial bore associatedtherewith, and into the region of the respective first and second fluidconduits in the housing, and vice versa.

Conveniently, the drill attachment is for use with a selection oftubular cutting members having various bore diameters. For example, thedrill attachment may be for use with cutting members having borediameters of around 20 to 250 mm and above.

Preferably, large diameter tubular cutting members, particularly thosefor use in dry drilling operations, have a plurality of extractionapertures in the base thereof, adjacent to the coupling means, in orderto accommodate larger dust extraction rates than are possible solelythrough the shank portion. Advantageously, tubular cutting membershaving a bore diameter greater than around 70 mm, and preferably greaterthan 80 mm, comprise dust extraction apertures in the base thereof.

In one embodiment, where large diameter tubular cutting members areused, an adapter may be provided which comprises the coupling means forcoupling to the end portion of the drive shaft, upon which adapter thetubular cutting member is mounted. Preferably, the adapter comprises aplurality of radially extending mounting pins which are received withinengaging slots provided in the tubular cutting member. This arrangementmay be described as a bayonet type fitting.

The adapter may comprise a male threaded portion provided on a shankportion for coupling to the end of the drive shaft. Thus, as notedabove, the shank portion may be indirectly coupled to the cuttingmember.

Preferably the shank portion includes a throughbore which permits fluidcommunication between the bore of the cutting member and one of thefirst and second fluid conduits in the housing, via the respective boresin the drive shaft.

Alternatively, the adapter may comprise a female threaded portion whichcouples to the end of the drive shaft, either directly, or indirectlyusing a double sided, male threaded, female-to-female thread adapter,for example.

Conveniently, tubular cutting members having a bore diameter greaterthan around 70 mm, and preferably greater than 80 mm are coupled to thedrive shaft using an adapter.

Preferably, the adapter further comprises a plurality of extractionapertures through which dust may also be extracted from the bore of thecutting member.

Preferably also, where dust extraction is effected through extractionapertures, either in the base of a tubular cutting member or through anadapter as described above, the dust is drawn into a chamber in thehousing and through one of the first and second fluid conduits.

The chamber is preferably an annular chamber defined between the outersurface of a portion of the drive shaft and the inner surface of aportion of the housing. Additionally, the chamber is preferably locatedwithin the region surrounding one of said first and second axial boresin the drive shaft. Preferably also, the chamber is open at one endproviding an opening through which dust may be drawn into said chamber.Thus, this arrangement requires that only one side of the drillingattachment is adapted for dry drilling when large bore cutting membersare used and dust is to be extracted through extraction apertures aswell as through a shank portion used to couple the cutting member to thedrive shaft. Preferably, the chamber is located at a first side of thedrill attachment and is in fluid communication with the first fluidconduit in the housing.

The side of the drilling attachment comprising the chamber may also beused for wet drilling, wherein means are provided for closing theopening through which dust is extracted into the chamber during drydrilling. Such means may include an annular body mounted within theopening, which annular body comprises a plurality of apertures whichremain open during dry drilling, but which are closed during wetdrilling to prevent leakage of drilling fluid. The apertures may beselectively opened and closed by use of an annular plate mounted on orwithin said annular body, which annular plate has correspondingapertures which are aligned with those of the annular body during dustextraction, but which are misaligned with the apertures of the annularbody, in order to close said apertures, during wet drilling. Preferably,a fluid sealing arrangement is provided between the annular body andannular plate in order to maintain sealing integrity and to preventleakage of the drilling fluid.

Advantageously, the chamber is in selective fluid communication with oneof the first and second fluid conduits in the housing, such that a fluidpath between the chamber and said fluid conduit is open when dust isextracted through the extraction apertures; that is, when large diametercutting members are used.

Selective fluid communication between the chamber and the fluid conduitmay be achieved by use of a sliding collar provided on the housing, andpreferably on the inner surface of the housing at the location of thechamber. The collar is preferably moveable in an axial direction from afirst position where the fluid path is closed, to a second positionwhere the fluid path is open.

Preferably, the drive shaft has an annular ring mounted on the outersurface thereof, said ring having substantially the same outer diameteras the inner diameter of the portion of the housing defining thechamber. Preferably, the ring is aligned with the fluid conduit in fluidcommunication with the chamber, and more preferably along thecentre-line thereof. Thus, when the collar is moved to close the fluidpath between the fluid conduit and the chamber, that is, towards a firstposition, a first end of the collar will abut a side face of the ring,therefore closing a portion of the fluid conduit and consequently saidfluid path. Thus, any dust extracted from the bore of the cutting memberwill be drawn through the throughbore in the shank portion, through therespective bores in the drive shaft, and subsequently through theportion of the fluid conduit which remains open. In this position, asecond end of the collar, opposite said first end, is substantiallyaligned with the opening of the chamber.

When large diameter cutting members are used in dry drilling operationswhere dust is extracted through the shank portion and extractionapertures, the collar is extended from the housing towards the second,open position, towards the base of the cutting member, wherein thesecond end of the collar is substantially aligned with the base of thecutting member. This, therefore, opens the fluid path between thechamber and the associated fluid conduit and also provides an enclosedpath through which dust may be extracted from the bore of the cuttingmember, through the extraction apertures and into the chamber within thehousing, substantially minimising the leakage of dust particles into theatmosphere.

Conversely, when small diameter cutting members are used in dry drillingoperations where dust is extracted through the throughbore in the shankportion only, the collar is retracted into the housing towards the firstposition, closing the fluid path between the chamber and the associatedfluid conduit. When the drill attachment is in use, closing said fluidpath will prevent re-circulation of extracted dust into the chamber andprevent any reduction in the extraction flow rate provided by a suctiondevice attached to said fluid conduit associated with said chamber.

Advantageously, the collar comprises a plurality of axially arrangedcircumferential depressions in the outer surface thereof, saiddepressions adapted to receive an inwardly extending lip provided on thehousing. In use, the interaction of the circumferential depressions andthe lip is to retain the collar in the desired position such that thecollar cannot inadvertently be pushed into or pulled from the housingduring a drilling operation, at least not without considerable forcebeing applied.

In an alternative, preferred embodiment, the collar includes a pluralityof longitudinal ribs circumferentially distributed about the outersurface of the collar, said ribs defining a number of depressionsadapted to receive an inwardly extending lip provided on the housing.

Preferably, tubular cutting members used with the drill attachment maybe used in both wet and dry drilling operations. However, large diametertubular cutting members having extraction apertures in the base thereofpreferably comprise means for blocking said apertures in order toprevent drilling fluid from pouring from the bore of the cutting member.Such blocking means may include, for example, plugs which are fittedwithin the apertures, or may alternatively include a plate rotatablymounted on the cutting member or appropriate adapter, said plate beingrotatable to selectively open and close the extract apertures.

Preferably, the blocking means includes a unitary component having aplurality of plugs each formed and arranged to be received within arespective extraction aperture. Advantageously, adjacent plugs of theunitary component may be joined together by a linking member orconnecting rib. Conveniently, the linking members may serve to provide ameans for removing the plugs of the unitary component from theextraction apertures. For example, the linking members may be adapted tobe gripped by the hand or gripped or levered with a tool such as agripping wrench or a screwdriver or the like.

In some circumstances, where it is required to drill into relativelythick walls or the like, an extension portion may be used. Saidextension portion may comprise an elongate tubular member having athroughbore and including threaded portions at either end thereof forcoupling to the drive shaft and a tubular cutting member or appropriatecutting member adapter. Thus, a fluid path will exist between the boreof the cutting member and one of the first and second fluid conduits inthe housing via the throughbore of the extension portion and therespective bores of the drive shaft.

Preferably, where large diameter cutting members are used in drydrilling operations and dust is to be extracted through extractionapertures, an additional tubular member is provided which surrounds theextension portion and provides an encased path for dust to be drawn fromthe bore of the cutting member and into the chamber of the drillattachment housing. The additional tubular member may be coupled to thedrill attachment via an appropriate adapter, and preferably via asimilar adapter to that used for large diameter cutting members, asdiscussed above.

Advantageously, means are provided to secure a pilot drill to the drillattachment. Such means may be provided on the drive shaft at at leastone end portion thereof. The pilot drill securing means may comprise atleast one grub screw which extends radially through the drive shaft andgrips a pilot drill located within one of the first and second axialbores. Where the at least one grub screw extends through the drive shaftat a portion of the shaft which is contained within the housing, accessto said at least one grub screw may be achieved through one of the firstand second fluid conduits in the housing of the drill attachment.

Preferably, the drive means is a drilling unit such as a hand heldelectric drill, pneumatic drill or hydraulic drill or the like.

The drive means may be coupled to the drive shaft by threaded couplingmeans, for example. Preferably, the drive means comprises a malethreaded portion which engages a female threaded portion provided on thedrive shaft.

Alternatively, the drive means may be coupled to the drive shaft via anadapter, one end of which adapter may comprise a male threaded portionfor coupling to the drive shaft, and the opposite end may comprise a pinadapted to be received in a chuck of the drive means, such as a threejaw Jacobs chuck or an SDS chuck, for example.

Applicant has conveniently termed the drill attachment of the presentinvention “MULTISWIVEL” (Trade Mark).

According to a second aspect of the present invention, there is provideda drill attachment for coupling a tubular cutting member having a boreto drive means for rotating the cutting member, said drill attachmentcomprising:

a housing defining a fluid conduit; and

a drive shaft rotatably mounted within the housing and having a fluidtransmitting end portion being in fluid communication with the fluidconduit and being adapted for coupling to a tubular cutting member, anda drive end portion being adapted for coupling to drive means, saidhousing and said drive shaft together defining a chamber having anopening in selective fluid communication with said fluid conduit.

Preferably, the opening of the chamber in selective fluid communicationwith fluid conduit is located at the end thereof adjacent the fluidtransmitting end portion of the drive shaft.

Preferably also, the fluid transmitting end portion of the drive shaftis in fluid communication with the fluid conduit via the chamber definedby the drive shaft and the housing.

Preferably, the chamber defined by the housing and the drive shaft is anannular chamber.

Advantageously, the drill attachment is adapted for use in both dry andwet drilling operations. Dry drilling, as noted herein, involvesextracting dust produced during a drilling operation from the bore ofthe cutting member. Wet drilling involves feeding a drilling fluid, suchas water, into the bore of the tubular cutting member during drilling,which lubricates the material being drilled and cools the cuttingmember, improving the drilling efficiency and increasing the useablelife of the cutting member.

Conveniently, the fluid transmitting end portion of the drive shaft isadapted for transmitting drilling fluid to the bore of a tubular cuttingmember.

Additionally, the fluid transmitting end portion of the drive shaft maybe adapted for transmitting dust extracted from the bore of a cuttingmember.

Preferably, the opening in the fluid chamber is adapted for transmittingdust extracted from the bore of a tubular cutting member.

Conveniently, when dry drilling is required, a suction device such as avacuum pump or domestic or industrial vacuum cleaner, is coupled to thefluid conduit in the housing. Alternatively, when wet drilling isrequired, a drilling fluid supply, such as a water supply, is coupled tothe fluid conduit defined by the housing.

A suction device or a fluid supply may be coupled to the fluid conduitvia an appropriate extraction or supply hose, which extraction or supplyhose may be connected to the fluid conduit using a threaded connectionor a jubilee clip or other suitable adjustable hose clip or the like.Alternatively, any hose may be connected to the fluid conduit by way ofa nipple and sliding collar arrangement or any other quick connectcoupling. However, it should be understood that any means of connectinga hose to the fluid conduit may be used as would readily be selected bya person of skill in the art.

Preferably, the drive shaft is bearing mounted within the housing of thedrill attachment. Preferably also, the drive shaft is retained withinsaid housing using circlips.

In a preferred embodiment of the present invention, the drive shaftcomprises an axial bore which extends partially through the drive shaftfrom the fluid transmitting end portion thereof, and terminates at apoint within the drive shaft. Conveniently, the drive shaft comprises atleast one radial bore which extends from the outer surface of the driveshaft and merges with said axial bore.

Advantageously, two radial bores are provided and are preferablydiametrically aligned such that a first diametric bore is defined whichextends through the drive shaft in a direction normal to the axialdirection of the drive shaft.

In an alternative embodiment, a number of radial bores are providedwhich are arranged to define a plurality of diametric bores distributedalong the length of the drive shaft.

Conveniently, the axial bore and said at least one radial bore permitfluid communication between the fluid transmitting end portion of thedrive shaft and the fluid conduit, via said chamber.

In a preferred embodiment, said axial bore and at least one radial boreare adapted for jointly transmitting dust from the bore of a tubularcutting member to the fluid conduit in the housing. Additionally, saidaxial bore and at least one radial bore are preferably adapted forjointly transmitting drilling fluid from the fluid conduit to the boreof a cutting member.

Advantageously, one end of a tubular cutting member for use with thedrill attachment comprises coupling means for coupling to the driveshaft, and another, opposite end of the tubular cutting member comprisescutting elements for effecting drilling.

Preferably, the cutting means includes threaded coupling means, wherein,for example, the tubular cutting member may comprise a male threadedportion which is received within a female threaded portion provided onthe fluid transmitting end portion of the drive shaft. Alternatively,the cutting member may comprise a female threaded portion which receivesa male threaded portion provided on the fluid transmitting end of thedrive shaft.

In a preferred embodiment, the drive shaft comprises means forpreventing rotation within the housing when a tubular cutting member iscoupled thereto using a threaded connection. Such rotation preventionmeans may be in the form of diametrically opposed land portions locatedon at least one of the fluid transmitting end and drive end of the driveshaft, said land portions providing gripping means for a tool torestrain the drive shaft from rotational motion. The land portions maybe adapted to be gripped by an open mouthed wrench or an adjustable pipewrench, or the like.

Conveniently, the coupling means of the tubular cutting member isprovided on a shank portion associated therewith. The shank portion maybe formed integrally with the cutting member or may be independentlycoupled thereto, as discussed in more detail below.

The shank portion preferably includes a throughbore, permitting fluidcommunication between the bore of the cutting member and the fluidconduit in the housing. preferably, the arrangement is such that fluidtransfer is possible through the throughbore in the shank portion,through the axial and at least one radial bores in the drive shaft,through the chamber defined by the drive shaft and the housing, andthrough the fluid conduit, and vice versa.

Conveniently, the drill attachment is for use with a selection oftubular cutting members having various bore diameters. For example, thedrill attachment may be for use with cutting members having borediameters of around 20 to 250 mm and above.

Preferably, large diameter tubular cutting members, particularly thosefor use in dry drilling operations, have a plurality of extractionapertures in the base thereof, adjacent to the coupling means, in orderto accommodate larger dust extraction rates than are possible solelythrough the shank portion. Advantageously, tubular cutting membershaving a bore diameter greater than around 70 mm, and preferably greaterthan 80 mm, comprise dust extraction apertures in the base thereof.

In one embodiment, where large diameter tubular cutting members areused, an adapter may be provided which comprises the coupling means forcoupling to the fluid transmitting end portion of the drive shaft, uponwhich adapter the tubular cutting member is mounted. Preferably, theadapter comprises a plurality of radially extending mounting pins whichare received within engaging slots provided in the tubular cuttingmember. This arrangement may be described as a bayonet type fitting.

The adapter may comprise a male threaded portion provided on a shankportion for coupling to the end of the drive shaft. Thus, as notedabove, the shank portion may be indirectly coupled to the cuttingmember. Preferably, the shank portion includes a throughbore whichpermits fluid communication between the bore of the cutting member andthe fluid conduit in the housing, via the bores in the drive shaft andvia the chamber defined by the drive shaft and the housing.

Alternatively., the adapter may comprise a female threaded portion whichcouples to the fluid transmitting end of the drive shaft, eitherdirectly, or indirectly using a double sided, male threaded,female-to-female thread adapter, for example.

Conveniently, tubular cutting members having a bore diameter greaterthan 80 mm are coupled to the drive shaft using an adapter.

Preferably, the adapter further comprises a plurality of extractionapertures through which dust may be extracted from the bore of thecutting member.

Preferably, where dust extraction is effected through extractionapertures, either in the base of a tubular cutting member or through anadapter as described above, the dust is drawn into the chamber via theopening thereof, which is selected to be in fluid communication with thefluid conduit.

To assist in dust extraction through extraction apertures in the base ofa tubular cutting member, the housing may comprise a sliding collar,which collar may be extended from the housing towards the base of atubular cutting member coupled to the drill attachment in order toprovide an encased fluid path between the extract apertures and theopening of the chamber.

Alternatively, the arrangement may be such that when a cutting member iscoupled to the drill attachment, the base of the cutting member issufficiently close to the opening in the chamber to eliminate therequirement for a sliding collar, as noted above.

In a preferred embodiment, where large bore tubular cutting members areused in dry drilling operations, dust is extracted from the bore of thecutting member through the throughbore of the shank portion and into thechamber via the bores of the drive shaft and additionally through theextract apertures in the base of the cutting member and into the chambervia the opening thereof.

Preferably, when small bore cutting members are used in dry drillingoperations, dust is extracted through the throughbore of the shankportion, through the bores of the drive shaft, into the chamber, andthrough the fluid conduit defined in the housing. In this arrangement,the opening of the chamber is selected to prevent any fluidcommunication between the opening and the fluid conduit in order toprevent dust escaping from the chamber and into the atmosphere.

When wet drilling is undertaken using large bore cutting members,drilling fluid is preferably transferred to the bore thereof through thefluid conduit into the chamber, through the bores of the drive shaft andthrough the throughbore in the shank portion. Preferably, the opening ofthe chamber is selected to prevent any fluid communication between saidopening and the fluid conduit in order to prevent spillage of thedrilling fluid from the chamber.

Conveniently, selective fluid communication between the opening of thechamber and the fluid conduit may be achieved by way of an annular bodymounted within the opening of the chamber, which annular body comprisesa plurality of apertures which may be selectively opened and closed byuse of an annular plate mounted on or within said annular body.Preferably, said annular plate has corresponding apertures which arealigned with those of the annular body to provide fluid communicationbetween the opening of the annulus and the fluid conduit, but which aremisaligned with the apertures of the annular body in order to close saidapertures, and thus prevent fluid communication. Preferably, a fluidsealing arrangement is provided between the annular body and annularplate in order to maintain sealing integrity and to prevent leakage ofthe drilling fluid.

Preferably, tubular cutting members used with the drill attachment maybe used in both wet and dry drilling operations. However, large diametertubular cutting members having extraction apertures in the base thereofpreferably comprise means for blocking said apertures in order toprevent drilling fluid from pouring from the bore of the cutting memberwhen used in wet drilling operations. Such blocking means may include,for example, plugs which are fitted within the extraction apertures, ormay alternatively include a plate rotatably mounted on the cuttingmember or appropriate adapter, said plate being rotatable to selectivelyopen and close the extraction apertures.

Preferably, the blocking means includes a unitary component having aplurality of plugs each formed and arranged to be received within arespective extraction aperture. Advantageously, adjacent plugs of theunitary component may be joined together by a linking member orconnecting rib. Conveniently, the linking members may serve to provide ameans for removing the plugs of the unitary component from theextraction apertures. For example, the linking members may be adapted tobe gripped by the hand or gripped or levered with a tool such as agripping wrench or a screwdriver or the like.

In some circumstances, where it is required to drill into relativelythick walls or the like, an extension portion may be used. Saidextension portion may comprise an elongate tubular member having athroughbore and including threaded portions at either end thereof forcoupling to the drive shaft and a tubular cutting member or appropriatecutting member adapter. Thus, a fluid path will exist between the boreof the cutting member and the fluid conduit defined in the housing viathe throughbore of the extension portion and the bores of the driveshaft.

Preferably, where large diameter cutting members are used in drydrilling operations and dust is to be extracted through extractionapertures, an additional tubular member is provided which surrounds theextension portion and provides an encased path for dust to be drawn fromthe bore of the cutting member and into the chamber in the drillattachment housing. The additional tubular member may be coupled to thedrill attachment via an appropriate adapter, and preferably via asimilar adapter to that used for large diameter cutting members, asdiscussed above.

Advantageously, means are provided to secure a pilot drill to the drillattachment. Such means may be provided on the drive shaft at at leastone end portion thereof. The pilot drill securing means may comprise atleast one grub screw which extends radially through the drive shaft andgrips a pilot drill located within one of the first and second axialbores. Where the at least one grub screw extends through the drive shaftat a portion of the shaft which is contained within the housing, accessto said at least one grub screw may be achieved through one of the firstand second fluid conduits in the housing of the drill attachment.

Preferably, the drive means is a drilling unit such as a hand heldelectric drill, pneumatic drill or hydraulic drill or the like.

The drive means may be coupled to the drive shaft by threaded couplingmeans, for example. Preferably, the drive means comprises a malethreaded portion which engages a female threaded portion provided on thedrive shaft.

Alternatively, the drive means may be coupled to the drive shaft via anadapter, one end of which adapter may comprise a male threaded portionfor coupling to the drive shaft, and the opposite end may comprise a pinadapted to be received in a chuck of the drive means, such as a threejaw Jacobs chuck or an SDS chuck, for example.

These and other aspects of the present invention will now be described,by way of example, with reference to the accompanying drawings, inwhich:

FIG. 1 is perspective view of a drill attachment for use in wet and drydrilling operations in accordance with one embodiment of one aspect ofthe present invention;

FIG. 2 is a sectional perspective view of a drill attachment inaccordance with another embodiment of the present invention;

FIG. 3 is a sectional perspective view of the drill attachment of FIG.1;

FIG. 4 is a sectional perspective view of the drill attachment of FIG. 1used in a dry drilling operation;

FIG. 5 is a sectional perspective view of the drill attachment of FIG. 1used in a wet drilling operation;

FIGS. 6 to 9 show sectional perspective views of the drill attachment ofFIG. 1 in alternative dry drilling arrangements;

FIGS. 10 to 12 show sectional perspective views of the drill attachmentof FIG. 1 in alternative wet drilling arrangements;

FIG. 13 is a perspective view of a drilling plug arrangement;

FIG. 14 is a perspective view of the drilling plug arrangement of FIG.13 shown in use;

FIG. 15 is an enlarged view of one end of the drill attachment;

FIG. 16 is an enlarged view of another end of the drill attachment;

FIGS. 17A, 17B, 18A and 18B are perspective views showing details of acollar portion of the drill attachment;

FIG. 19 is a perspective view of a collar portion of the drillattachment in accordance with an alternative embodiment of the presentinvention; and

FIGS. 20 and 21 are alternative cross-sectional views of a drillattachment for use in wet and dry drilling operations in accordance withanother aspect of the present invention.

Reference is first made to FIG. 1 in which there is shown a perspectiveview of a drill attachment 10 for use in dry and wet drillingoperations. The drill attachment comprises a housing 12 having a firstfluid conduit 14 adapted for connecting to a suction device (not shown)and a second fluid conduit 16 adapted for connecting to a fluid supply(not shown). The drill attachment also comprises a drive shaft 18rotatably mounted within the housing 12, the drive shaft being adaptedfor transmitting rotary motion from a drill unit to a tubular cuttingmember. As shown in FIG. 1, the first and second fluid conduits 14, 16are disposed at 90° to each other. However, in alternative embodiments,the first and second fluid conduits may be disposed at any relativeangle, such as is shown in FIG. 2 which is a cross-sectional view of adrill attachment 1 with the first and second fluid conduits 14, 16 beingaligned in the same plane.

Reference is now made to FIG. 3 in which there is shown a sectionalperspective view of the drill attachment 10 shown in FIG. 1. As notedabove, the drill attachment 10 comprises a housing 12 within which adrive shaft 18 is rotatably mounted via bearings 20. The drive shaft 18is retained within the housing 12 of the drill attachment via a circlip21. The drive shaft 18 has fluid transmitting first and second ends 22,24 which are in fluid communication with the respective first and secondfluid conduits 14, 16, said first end 22 being adapted for coupling toone of a tubular cutting member and a drive means such as a drill unitand the second end 24 being adapted for coupling to the other of thetubular cutting member and the drive means.

The drive shaft 18 comprises a first axial bore 26 which extendspartially through the drive shaft from the first end 22 thereof, andterminates at a point 28 within the drive shaft. The drive shaftadditionally comprises a first diametric bore 30 which extends throughthe drive shaft and merges with the first axial bore 26 in the region ofthe terminating end 28 of the first axial bore. Thus, fluidcommunication between the first end 22 of the drive shaft 18 and thefirst fluid conduit 14 is achieved via the first axial and diametricbores 26, 30 in the drive shaft 18.

Similarly, the drive shaft 18 also comprises a second axial bore 32which extends from the second end 24 thereof, and terminates at a point34 within the drive shaft. Also provided is a second diametric bore 36which extends through the drive shaft 18 and merges with the terminatingend 34 of the second axial bore 32. Accordingly, fluid communicationbetween the second end 24 of the drive shaft 18 and the second fluidconduit 16 (FIG. 1) is achieved via the second axial and diametric bores32, 36 in the drive shaft.

The drill attachment 10 shown in FIG. 3 also comprises an annularchamber 38 which is open at one end 39, which chamber 38 is in selectivefluid communication with the first fluid conduit 14 by way of a collar40 slidably mounted on the inner surface of the housing 12.

The collar 40 is moveable in an axial direction from a first position,as shown in FIG. 3, where a fluid path between the chamber and the firstfluid conduit 14 is closed, and a second position where a fluid path isopened. When the collar 40 is located in a first position, the end ofthe collar 40 abuts a side face of a ring 42 mounted on the drive shaft.

The chamber 38 is used for dust extraction when larger diameter tubularcutting members are used, wherein the collar 40 is moved to a secondposition to open a fluid path between the chamber 38 and the first fluidconduit 14, allowing dust to be extracted from the bore of a tubularcutting member, into the chamber 38 via annular opening 39, and throughthe first fluid conduit 14. The use of the chamber 38 for dustextraction with larger diameter cutting members will be discussed inmore detail below.

As shown in FIG. 4, when a drilling operation is required to beundertaken with dust extraction, a drill unit (not shown) is coupled tothe second end 24 of the drive shaft 18 via an adapter 44, a tubularcutting member 46 is coupled to the first end 22 of the drive shaft 18,and a suction device (not shown) is connected to the first fluid conduit14. In the embodiment shown, the cutting member 46 is coupled to thefirst end 22 of the drive shaft 18 via a shank portion 50 whichcomprises a male threaded portion 52 which is received within a femalethreaded portion 54 provided in the first end 22 of the drive shaft 18.As shown, the shank portion 50 is formed integrally with the tubularcutting member 46 and comprises a throughbore 56. Thus, dust producedwhile drilling may be extracted from the bore 48 of a cutting member,through the throughbore 56 in the shank portion 50, through the bores26, 30 in the drive shaft 18, and through the first fluid conduit 14.

When dust extraction is undertaken using a smaller diameter cuttingmember 46 as shown in FIG. 4, the collar 40 is located in its firstposition in order to close a fluid path between the annulus 38 and thefirst fluid conduit 14 in order to prevent extracted dust to escape intothe atmosphere through the annular opening 39.

A wet drilling arrangement will now be described with reference to FIG.5 in which there is shown a further sectional perspective view of thedrill attachment 10. Where a wet drilling operation is required to beundertaken, the drill unit (not shown) is coupled to the first end 24 ofthe drive shaft via an adapter 44 and the tubular cutting member 46 iscoupled to the second end 24, wherein the male threaded portion 52 onthe shank portion 50 is received within a female threaded portion 58provided in the second end 24 of the drive shaft. A drilling fluidsupply, such as a water supply, is coupled to the second fluid conduit16 (FIG. 1) and fluid is transmitted through the second fluid conduit16, through the bores 32, 36 in the drive shaft 18, through thethroughbore 56 of the shank portion 50, and into the bore 48 of thetubular cutting member 46.

In order to prevent leakage of drilling fluid from the drill attachment10, fluid seals 60 are provided on either side of the second diametricbore 36 of the drive shaft.

Reference is now made to FIG. 6 in which there is shown a sectionalperspective view of the drill attachment 10 when used in a dry drillingoperation with a larger diameter tubular cutting member 62. As beforethe cutting member 62 is coupled to the first end 22 of the drive shaft18 via a shank portion 50 having a throughbore 56. In this instance, thetubular cutting member 62 comprises a plurality of extraction apertures64 in the base thereof, through which extraction apertures 64 dust mayadditionally be extracted from the bore 66 of the cutting member 62.

In the same way as discussed above, a suction device (not shown) isconnected to the first fluid conduit 14 and dust is extracted from thebore 66 of the cutting member 62 through the throughbore 56 in the shankportion 50, through the bores 26, 30 in the drive shaft 18, and throughthe first fluid conduit 14. However, dust is also extracted through thefluid conduit 14 via the chamber 38. This is achieved by extending thecollar 40 from the housing 12 towards the base of the cutting member 62such that the collar 40 is located in a second position wherein a fluidpath between the chamber 38 and the first fluid conduit 14 is opened.When extended, the collar provides an encased path through which dustextracted through the extraction apertures 64 in the base of the cuttingmember 62 may pass into the chamber 38, substantially minimising theleakage of dust particles into the atmosphere.

An alternative arrangement is shown in FIG. 7 of the drawings whereinthe drill attachment 10 is shown in a dry drilling arrangement with alarge diameter cutting member 68 coupled thereto. The cutting member 68is coupled to the first end 22 of the drive shaft 18 via two adapters, acutting member adapter 70 and a coupling adapter 72. The cutting member68 is mounted on the cutting member adapter 70 via a bayonet typefitting 74, and the cutting member adapter 70 is coupled to the driveshaft 18 via the coupling adapter 72.

As shown in FIG. 7, the cutting member adapter 70 comprises a centralbore 76 having a female threaded portion 78 for coupling to the couplingadapter 72. Additionally, the cutting member adapter 70 comprises aplurality of extract apertures 80 through which dust may be extractedfrom the bore 82 of the cutting member 68.

The coupling member 72 comprises a male threaded portion 84 on eitherend thereof, the male threaded portions 84 for coupling to the femalethreaded portion 78 in the cutting member adapter 70 and the femalethreaded portion 54 in the first end 22 of the drive shaft 18.Additionally, the coupling adapter 72 comprises a throughbore 86 throughwhich dust may be transmitted from the bore 82 of the cutting member 68to the first fluid conduit 14 via the bores 26, 30 in the drive shaft18.

In use, a suction device (not shown) is connected to the first fluidconduit 14 and the collar 40 is moved towards the cutting member.adapter 70 in order to open the fluid path between the fluid conduit 14and the chamber 38 and to provide an encased path through which dustextracted from the bore 82 of the cutting member 68 via the extractionapertures 80 may pass. Additionally, a drive unit (not shown) is coupledto the second end 24 of the drive shaft via adapter 44.

Reference is now made to FIG. 8 in which there is shown an arrangementof the present invention for use in drilling into relatively thick wallsor the like when dust extraction is required. A cutting member 88 havinga bore 90 is coupled to the first end 22 of the drive shaft 18 via anextension portion 92 which has a throughbore 94 for transmitting dusttherethrough and comprises threaded portions 96 at either end thereoffor coupling to the cutting member 88 and the drive shaft 18. As shownin FIG. 8, the cutting member 88 is coupled to the extension portion 92and the extension portion 92 is coupled to the drive shaft 18 via amale-to-female thread extension adapters 98. It should be noted thatsaid extension adapters 98 are only required in this instance due to thepresence of a tubular member 100, which is more clearly shown in FIG. 9.The tubular member 100 provides an annular path 102 through which dustmay pass from the bore 90 of the cutting member 88 via extractionapertures 104 and into the chamber 38 in the drill attachment 10, andsubsequently through the fluid conduit 14.

In order to allow transmission of dust from the annular path 102 intothe chamber 38 in the drill attachment 10, the tubular member 100comprises a plurality of apertures 106 in the base thereof adjacent theannular opening 39 in the drill attachment.

Referring to FIG. 10, the drill attachment 10 is shown for use in wetdrilling wherein thick wall portions or the like are to be drilled. Atubular cutting member 110 is coupled to the second end 24 of the driveshaft 18 via an extension portion 112 which has a throughbore 114 fortransmitting fluid therethrough and comprises threaded portions 116, 118at either end thereof for coupling to the drive shaft 18 and the cuttingmember 110 respectively.

The extension portion 112 is more clearly seen in FIG. 11 where it isshown that threaded portion 116 is a male threaded portion which couplesto the female threaded portion 58 of the second end 24 of the driveshaft, and threaded portion 118 is a female threaded portion whichreceives a male threaded portion 52 provided on a shank portion 50 ofthe cutting member 110.

Thus, where wet drilling is to be undertaken with the use of anextension member 112, a fluid supply is connected to the second fluidconduit 16 (FIG. 1) and fluid is transmitted through the fluid conduit116, through the bores 32, 36 in the drive shaft 18, through thethroughbore 114 in the extension member 112, through the throughbore 56in the shank portion 50, and into the bore 120 of the cutting member110.

A similar arrangement as that shown in FIGS. 10 and 11 is shown in FIG.12 in which a larger diameter tubular cutting member 122 is coupled tothe second end 24 of the drive shaft 18. In the embodiment shown, thecutting member is coupled to the drill attachment via an 25 extensionportion 112. However, it should be noted that the cutting member 122 maybe coupled directly to the drive shaft 18 of the drill attachment 10.

The cutting member 122 shown in FIG. 12 comprises extract apertures 124in the base thereof which have been blocked by a number of individualplugs 126 to prevent drilling fluid from pouring from the bore 128 ofthe cutting member. The provision of such plugs 126 allows cuttingmembers, such as those shown in FIGS. 6 and 7, to be used in both dryand wet drilling operations, eliminating the requirement for drillsdedicated to only one type of drilling.

An alternative plug arrangement is shown in FIGS. 13 and 14. Referringinitially to FIG. 13, a perspective view of a unitary blocking component400 is shown, which unitary component 400 includes a plurality of plugs402 joined together by linking members 404. As shown in FIG. 14, theplugs 402 are formed and arranged to be received within a respectiveextraction aperture of a tubular cutting member 406. The linking members404 allow the unitary blocking component 400 to be readily removed fromthe apertures of the tubular cutting member 406 in that they provide ameans to be gripped or levered by a tool such as a gripping wrench or ascrew driver or the like.

Reference is now made to FIG. 15 in which there is shown an enlargedview of the first end 22 of the drive shaft 18 of the drill attachment10. A pilot drill 130 is shown mounted within the first axial bore 26 ofthe drive shaft 18. The pilot drill 130 is secured within the firstaxial bore 26 by two grub screws 132 which extend radially through thedrive shaft 18 and grip a portion of reduced diameter 134 on the pilotdrill 130.

Access to said grub screws is achieved through the first fluid conduit14 in the housing 12 of the drill attachment 10.

Referring now to FIG. 16, there is shown an expanded view of the secondend 24 of the drive shaft 18, upon which second end 24 there is providedmeans for preventing the drive shaft 18 from rotating when tubularcutting member is coupled thereto, such rotation prevention means are inthe form of diametrically opposed land portions 136 located on the driveshaft 18 at the second end 24 thereof, said land portions 136 providinggripping means for a tool to restrain the drive shaft 18 from rotationalmotion. The land portions 136 may be adapted to be gripped by an openmouthed wrench or an adjustable pipe wrench, or the like.

Various features of the collar 40 of the drill attachment 10 inaccordance with one embodiment of the present invention will now bedescribed with reference to FIGS. 17A, 17B, 18A and 18B. Referringinitially to FIG. 17A, the collar 40 comprises a number of axiallyarranged circumferential depressions 300, which depressions 300 receivean inwardly extending lip 302 provided on the housing 12 of the drillattachment 10. A more detailed view is shown in FIG. 17B. The purpose ofthe circumferential depressions 300 and the lip 302 is to retain thecollar 40 in the desired position such that the collar 40 cannotinadvertently be pulled from or pushed back into the housing 12 during adrilling operation, at least not without considerable force beingapplied. Additionally, the presence of the depressions 300 enables thecollar 40 to be retained in a range of extended locations in order toaccommodate various sizes of tubular cutting members.

Referring now to FIGS. 18A and 18B, the collar 40 25 includes aplurality of protruding portions 304 which abut the base of a largetubular cutting member during a dry drilling operation in order thatwear is restricted to the protruding portions 304 and not the face 306of the collar 40.

An alternative embodiment of a drill collar 40 a in accordance with thepresent invention will now be described with reference to FIG. 19. Inthis embodiment, the collar 40 a includes a plurality of longitudinalribs 410 circumferentially distributed about the outer surface of thecollar 40 a. Each rib defines a, number of depressions along the lengththereof which are adapted to receive the inwardly extending lip 302(FIGS. 17A and 17B). As with the embodiment shown in FIGS. 18A and 18B,the collar 40 a of FIG. 19 also includes a plurality of protrudingportions 412.

An alternative embodiment of the present invention will now bedescribed, initially with reference to FIG. 120. A drill attachment 200for use in wet and dry drilling operations is shown, which drillattachment 200 comprises a housing 202 defining a fluid conduit 204 anda drive shaft 206 rotatably mounted within said housing 202. The driveshaft 206 comprises a fluid transmitting end portion 208 for coupling toa tubular cutting member, and a drive end portion 210 for coupling to adrill unit (not shown), said drive shaft 206 adapted for transmittingrotary motion from the drill unit to the tubular cutting member. Thefluid transmitting end portion 208 of the drive shaft 206 is in fluidcommunication with the fluid conduit 204 via an annular chamber 212defined between the housing and the drive shaft. The annular chamber 212has an opening 214 located at the end of the housing 202 adjacent thefluid transmitting end 208 of the drive shaft 206, said opening 214 ofthe annular chamber being in selective fluid communication with thefluid conduit 204.

Selective fluid communication between the opening 214 of the annularchamber 212 and the fluid conduit 204 is achieved by way of an annularbody 216 mounted within said opening 214, said annular body 216comprising a plurality of fluid apertures 218 which are selectivelyopened and closed by use of an annular plate 220 rotatably mountedwithin the housing 202. The annular plate 220 has corresponding fluidapertures 222 which are aligned with those of the annular body 216 toprovide fluid communication between the opening 214 and the fluidconduit 204, but which are misaligned with the apertures 218 of theannular body 216 in order to close said apertures 218, and thus preventfluid communication.

Fluid communication between the fluid transmitting end 208 and the fluidconduit 204 via the chamber 212 is accomplished via an axial bore 224 inthe drive shaft which extends from the fluid transmitting end 208, and adiametric bore 226 which extends through the drive shaft 206 and mergeswith the axial bore 224.

Thus, during a dry drilling operation, dust may be extracted from thebore of a tubular cutting member, through the bores 224, 226 in thedrive shaft 206, into the annular chamber 212, and through the fluidconduit 204, to which a suction device (not shown) is attached.Additionally, during a dry drilling operation using a large diametercutting member 227, dust may be extracted from the bore of the cuttingmember through the opening in 214 of the chamber 212, into the chamber212, and through the fluid conduit 204, This arrangement is possiblewhen the apertures 218, 220 of the annular body 216 and annular body 220are aligned, as shown in FIG. 20.

However, during dry drilling with small diameter cutting members, theapertures 218, 222 of the annular body and plate 216, 220 aremisaligned, as shown in FIG. 21, such that dust extracted from the boreof a cutting member 228 through the bores 224, 226 of the drive shaft206 will not escape through the opening 214 of the chamber 212.

Additionally, during a wet drilling operation, the apertures 218, 222 ofthe annular body and plate 216, 220 respectively are misaligned so thatdrilling fluid supplied from an external fluid supply into the chamber212 will not escape through the opening 214 in the chamber 212.

It should be understood that the embodiments hereinbefore described aremerely exemplary of the present invention and various modifications maybe made thereto without departing from the scope of the invention. Forexample, in the embodiments shown in FIGS. 1 to 19, each end 22, 24 ofthe drive shaft 18 may be adapted for transmitting both dust anddrilling fluid. Additionally, the drill unit may be directly coupled tothe required end of the drive shaft without the requirement for anadapter.

1. A drill attachment for coupling a tubular cutting member having abore to drive means for rotating the cutting member, the drillattachment comprising: a housing defining first and second fluidconduits; and a drive shaft rotatably mounted within the housing andhaving fluid transmitting first and second end portions in fluidcommunication with the respective first and second fluid conduits, thefirst end portion being adapted for coupling to one of a tubular cuttingmember and a drive means and the second end portion being adapted forcoupling to the other of the tubular cutting member and the drive means;and wherein one of said first and second end portions of the drive shaftis adapted for coupling to a tubular cutting member when dry drilling isrequired, and the other of said first and second end portions is adaptedfor coupling to a tubular cutting member when wet drilling is required.2. A drill attachment as claimed in claim 1, wherein at least one ofsaid first and second end portions of the drive shaft is adapted forcoupling to a tubular cutting member when dry drilling is required.
 3. Adrill attachment as claimed in claim 1, wherein at least one of saidfirst and second end portions of the drive shaft is adapted for couplingto a tubular cutting member when wet drilling is required.
 4. A drillattachment as claimed in claim 1, wherein at least one of said first andsecond end portions of the drive shaft is adapted for transmitting dustextracted from the bore of a tubular cutting member, and at least one ofsaid first and second end portions of the drive shaft is adapted fortransmitting an appropriate drilling fluid such as water to the bore ofa tubular cutting member.
 5. A drill attachment as claimed in claim 1,wherein one of said first and second fluid transmitting end portions ofthe drive shaft is adapted for transmitting dust extracted from the boreof a tubular cutting member, and the other of said first and second endportions of the drive shaft is adapted for transmitting water or otherappropriate drilling fluid to the bore of a tubular cutting member.
 6. Adrill attachment as claimed in claim 1, wherein when dry drilling isrequired, a suction device is coupled to one of the first and secondfluid conduits in the housing.
 7. A drill attachment as claimed in claim1, wherein when wet drilling is required, a drilling fluid supply iscoupled to one of the fluid conduits in the housing.
 8. A drillattachment as claimed in claim 1, wherein one of said first and secondfluid conduits is adapted for coupling to a suction device, and theother of said first and second fluid conduits is adapted for coupling toa fluid supply.
 9. A drill attachment as claimed in claim 1, wherein thedrive shaft is bearing mounted within the housing of the drillattachment.
 10. A drill attachment as claimed in claim 1, wherein thedrive shaft is retained within said housing using circlips.
 11. A drillattachment as claimed in claim 1, wherein the drive shaft comprises afirst axial bore which extends partially through the drive shaft fromthe first fluid transmitting end portion thereof, and terminates at apoint within the drive shaft.
 12. A drill attachment as claimed in claim11, wherein the drive shaft comprises at least one radial bore whichextends from the outer surface of the drive shaft and merges with saidfirst axial bore.
 13. A drill attachment as claimed in claim 12, whereinsaid at least one radial bore merges with the first axial bore in theregion of a terminating end of said first axial bore.
 14. A drillattachment as claimed in claim 12, wherein two radial bores are providedand are diametrically aligned such that a first diametric bore isdefined which extends through the drive shaft in a direction normal tothe axial direction of the drive shaft.
 15. A drill attachment asclaimed in claim 1, wherein one end of a tubular cutting member for usewith the drill attachment comprises coupling means for coupling to thedrive shaft, and another opposite end of the tubular cutting membercomprises cutting elements for effecting drilling.
 16. A drillattachment as claimed in claim 15, wherein the coupling means includesthreaded coupling means.
 17. A drill attachment as claimed in claim 16,wherein the tubular cutting member comprises a male threaded portionwhich is received within a female threaded portion provided on an endportion of the drive shaft.
 18. A drill attachment as claimed in claim16, wherein the cutting member comprises a female threaded portion whichreceives a male threaded portion provided at an end portion of the driveshaft.
 19. A drill attachment as claimed in claim 15, wherein thecoupling means of the tubular cutting member is provided on a shankportion associated therewith.
 20. A drill attachment as claimed in claim19, wherein the shank portion is formed integrally with the cuttingmember.
 21. A drill attachment as claimed in claim 19, wherein the shankportion is independently coupled to the coupling member.
 22. A drillattachment as claimed in claim 19, wherein the shank portion includes athroughbore permitting fluid transmission between the bore of thecutting member and one of the first and second fluid conduits in thehousing when in use.
 23. A drill attachment as claimed in claim 15,wherein large diameter tubular cutting members, particularly those foruse in dry drilling operations, have a plurality of extraction aperturesin the base thereof, adjacent to the coupling means.
 24. A drillattachment as claimed in claim 23, wherein tubular cutting membershaving a bore diameter greater than around 70 mm comprise dustextraction apertures in the base thereof.
 25. A drill attachment asclaimed in claim 23, wherein where dust extraction is effected throughextraction apertures, the dust is drawn into a chamber in the housingand through one of the first and second fluid conduits.
 26. A drillattachment as claimed in claim 25, wherein the chamber is an annularchamber defined between the outer surface of a portion of the driveshaft and the inner surface of a portion of the housing.
 27. A drillattachment as claimed in claim 26, wherein the chamber is located withinthe region surrounding one of said first and second axial bores in thedrive shaft.
 28. A drill attachment as claimed in claim 25, wherein thechamber is open at one end providing an opening through which dust maybe drawn into said chamber.
 29. A drill attachment as claimed in claim28, wherein only one side of the drilling attachment is adapted for drydrilling when large bore cutting members are used and dust is to beextracted through extraction apertures as well as through a shankportion used to couple the cutting member to the drive shaft.
 30. Adrill attachment as claimed in claim 25, wherein the chamber is locatedat a first side of the drill attachment and is in fluid communicationwith the first fluid conduit in the housing.
 31. A drill attachment asclaimed in claim 25, wherein the chamber is in selective fluidcommunication with one of the first and second fluid conduits in thehousing, such that a fluid path between the chamber and said fluidconduit is open when dust is extracted through extraction apertures. 32.A drill attachment as claimed in claim 1, wherein the drive shaftcomprises means for preventing rotation within the housing when atubular cutting member is coupled thereto using a threaded connection.33. A drill attachment as claimed in claim 32, wherein the rotationprevention means is in the form of diametrically opposed land portionslocated at at least one end portion of the drive shaft, said landportions providing gripping means for a tool to restrain the drive shaftfrom rotational motion.
 34. A drill attachment as claimed in claim 1,wherein the drill attachment is adapted for use with a selection oftubular cutting members having various bore diameters.
 35. A drillattachment as claimed in claim 34, wherein the drill attachment isadapted for use with cutting members having bore diameters of around 20to 250 mm and above.
 36. A drill attachment as claimed in claim 1,wherein where large diameter tubular cutting members are used, anadapter is provided which comprises the coupling means for coupling tothe end portion of the drive shaft, upon which adapter the tubularcutting member is mounted.
 37. A drill attachment as claimed in claim36, wherein the adapter comprises a plurality of radially extendingmounting pins which are received within engaging slots provided in thetubular cutting member.
 38. A drill attachment as claimed in claim 36,wherein tubular cutting members having a bore diameter greater thanaround 70 mm are coupled to the drive shaft using an adapter.
 39. Adrill attachment as claimed in claim 36, wherein the adapter furthercomprises a plurality of extraction apertures.
 40. A drill attachment asclaimed in claim 1, wherein the drive shaft has an annular ring mountedon the outer surface thereof, said ring having substantially the sameouter diameter as the inner diameter of the portion of the housingdefining the chamber.
 41. A drill attachment as claimed in claim 40,wherein a chamber is defined in the housing into which chamber dust isdrawn through one of the first and second fluid conduits and the annularring is aligned with the fluid conduit in fluid communication with thechamber.
 42. A drill attachment as claimed in claim 41, wherein the ringis aligned along the centre-line of the fluid conduit in fluidcommunication with the chamber.
 43. A drill attachment as claimed inclaim 1, wherein tubular cutting members used with the drill attachmentmay be used in both wet and dry drilling operations.
 44. A drillattachment as claimed in claim 43, wherein large diameter tubularcutting members having extraction apertures in the base thereof comprisemeans for blocking said apertures in order to prevent drilling fluidfrom pouring from the bore of the cutting member during a wet drillingoperation.
 45. A drill attachment as claimed in claim 44, wherein saidblocking means includes plugs which are fitted within the apertures. 46.A drill attachment as claimed in claim 44, wherein the blocking meansincludes a unitary component having a plurality of plugs each formed andarranged to be received within a respective extraction aperture.
 47. Adrill attachment as claimed in claim 46, wherein adjacent plugs of theunitary component may be joined together by a linking member.
 48. Adrill attachment as claimed in claim 47, wherein the linking membersserves to provide a means for removing the plugs of the unitarycomponent from the extraction apertures.
 49. A drill attachment asclaimed in claim 1, wherein the drilling attachment is adapted to becoupled to a tubular cutting member via an extension portion.
 50. Adrill attachment as claimed in claim 49, wherein said extension portioncomprises an elongate tubular member having a throughbore and includingthreaded portions at either end thereof for coupling to the drive shaftand a tubular cutting member or appropriate cutting member adapter. 51.A drill attachment as claimed in claim 49, wherein where large diametercutting members are used in dry drilling operations and dust is to beextracted through extraction apertures, an additional tubular member isprovided which surrounds the extension portion and provides an encasedpath for dust to be drawn from the bore of the cutting member and intothe drill attachment housing.
 52. A drill attachment as claimed in claim51, wherein the additional tubular member is coupled to the drillattachment via an appropriate adapter.
 53. A drill attachment as claimedin claim 1, wherein means are provided to secure a pilot drill to thedrill attachment.
 54. A drill attachment as claimed in claim 53, whereinsaid means for securing a pilot drill to the drill attachment may beprovided on the drive shaft at at least one end portion thereof.
 55. Adrill attachment as claimed in claim 53, wherein the means for securinga pilot drill to the drill attachment comprises at least one grub screwwhich extends radially through the drive shaft and grips a pilot drilllocated within one of the first and second axial bores.
 56. A drillattachment as claimed in claim 55, wherein where the at least one grubscrew extends through the drive shaft at a portion of the shaft which iscontained within the housing, access to said at least one grub screw maybe achieved through one of the first and second fluid conduits in thehousing of the drill attachment.
 57. A drill attachment as claimed inclaim 1, wherein the drive means is a drill.
 58. A drill attachment asclaimed in claim 1, wherein the drive means is coupled to the driveshaft by threaded coupling means.
 59. A drill attachment as claimed inclaim 1, wherein the drive means comprises a male threaded portion whichengages a female threaded portion provided on the drive shaft.
 60. Adrill attachment as claimed in claim 1, wherein the drive means iscoupled to the drive shaft via an adapter.
 61. A drill attachment asclaimed in claim 60, wherein one end of the adapter comprise a malethreaded portion adapted to be coupled to the drive shaft, and theopposite end comprises a pin adapted to be received in a chuck of thedrive means.
 62. A drill attachment for coupling a tubular cuttingmember having a bore to drive means for rotating the cutting member, thedrill attachment comprising: a housing defining first and second fluidconduits; and a drive shaft rotatably mounted within the housing andhaving fluid transmitting first and second end portions in fluidcommunication with the respective first and second fluid conduits, thefirst end portion being adapted for coupling to one of a tubular cuttingmember and a drive means and the second end portion being adapted forcoupling to the other of the tubular cutting member and the drive means;wherein the drive shaft comprises a first axial bore which extendspartially through the drive shaft from the first fluid transmitting endportion thereof, and terminates at a point within the drive shaft; andwherein the drive shaft comprises a second axial bore which extendspartially through the drive shaft from the second fluid transmitting endportion thereof, and terminates at a point within the drive shaft.
 63. Adrill attachment as claimed in claim 62, wherein the drive shaft furthercomprises at least one radial bore which extends from the outer surfaceof the drive shaft and merges with said second axial bore.
 64. A drillattachment as claimed in claim 63, wherein two radial bores are providedand are preferably diametrically aligned such that a second diametricbore is defined which extends through the drive shaft in a directionnormal to the axial direction of the drive shaft.
 65. A drill attachmentas claimed in claim 63, wherein the location of said radial bores alongthe length of the drive shaft is such that said bores are substantiallyaligned with said respective first and second fluid conduits in thehousing.
 66. A drill attachment as claimed in claim 65, wherein one ofsaid first and second axial bores and associated at least one radialbore in the drive shaft is adapted for transmitting dust from the boreof a cutting member to the respective fluid conduit in the housing. 67.A drill attachment as claimed in claim 66, wherein the other of saidfirst and second axial bores and associated at least one radial bore isadapted for transmitting a drilling fluid from the respective fluidconduit in the housing to the bore of a cutting member.
 68. A drillattachment as claimed in claim 67, wherein the drive shaft comprisesfluid seals located on either side of the at least one radial borethrough which drilling fluid may be supplied in order to prevent leakageof said drilling fluid.
 69. A drill attachment for coupling a tubularcutting member having a bore to drive means for rotating the cuttingmember, the drill attachment comprising: a housing defining first andsecond fluid conduits: and a drive shaft rotatably mounted within thehousing and having fluid transmitting first and second end portions influid communication with the respective first and second fluid conduits,the first end portion being adapted for coupling to one of a tubularcutting member and a drive means and the second end portion beingadapted for coupling to the other of the tubular cutting member and thedrive means; wherein where dust extraction is effected throughextraction apertures, the dust is drawn into a chamber in the housingand through one of the first and second fluid conduits; wherein thechamber is located at a first side of the drill attachment and is influid communication with the first fluid conduit in the housing; andwherein the side of the drilling attachment comprising the chamber isalso adapted for use in wet drilling, wherein means are provided forclosing the opening through which dust is extracted into the chamberduring dry drilling.
 70. A drill attachment as claimed in claim 69,wherein such means includes an annular body mounted within the opening,which annular body comprises a plurality of apertures which remain openduring dry drilling, but which are closed during wet drilling to preventleakage of drilling fluid.
 71. A drill attachment as claimed in claim70, wherein the apertures are selectively opened and closed by use of anannular plate mounted on or within said annular body, which annularplate has corresponding apertures which are aligned with those of theannular body during dust extraction, but which are misaligned with theapertures of the annular body, in order to close said apertures, duringwet drilling.
 72. A drill attachment as claimed in claim 71, wherein afluid sealing arrangement is provided between the annular body andannular plate in order to maintain sealing integrity and to preventleakage of the drilling fluid.
 73. A drill attachment for coupling atubular cutting member having a bore to drive means for rotating thecutting member, the drill attachment comprising: a housing definingfirst and second fluid conduits; and a drive shaft rotatably mountedwithin the housing and having fluid transmitting first and second endportions in fluid communication with the respective first and secondfluid conduits, the first end portion being adapted for coupling to oneof a tubular cutting member and a drive means and the second end portionbeing adapted for coupling to the other of the tubular cutting memberand the drive means; wherein where dust extraction is effected throughextraction apertures, the dust is drawn into a chamber in the housingand through one of the first and second fluid conduits; wherein thechamber is in selective fluid communication with one of the first andsecond fluid conduits in the housing, such that a fluid path between thechamber and said fluid conduit is open when dust is extracted throughextraction apertures; and wherein selective fluid communication betweenthe chamber and the fluid conduit is achieved by use of a sliding collarprovided on the housing.
 74. A drill attachment as claimed in claim 73,wherein the sliding collar is provided on the inner surface of thehousing at the location of the chamber.
 75. A drill attachment asclaimed in claim 73, wherein the collar is moveable in an axialdirection from a first position where the fluid path is closed, to asecond position where the fluid path is open.
 76. A drill attachment asclaimed in claim 75, wherein when the collar is moved to close the fluidpath between the fluid conduit and the chamber, that is, towards a firstposition, a first end of the collar will abut a side face of the ring,therefore closing a portion of the fluid conduit and consequently saidfluid path.
 77. A drill attachment as claimed in claim 75, wherein whenlarge diameter cutting members are used in dry drilling operations wheredust is extracted through the shank portion and extraction apertures,the collar is extended from the housing towards the second, openposition, towards the base of the cutting member, wherein the second endof the collar is substantially aligned with the base of the cuttingmember.
 78. A drill attachment as claimed in claim 75, wherein whensmall diameter cutting members are used in dry drilling operations wheredust is extracted through the throughbore in the shank portion only, thecollar is retracted into the housing towards the first position, closingthe fluid path between the chamber and the associated fluid conduit. 79.A drill attachment as claimed in claim 73, wherein the collar comprisesa plurality of axially arranged circumferential depressions in the outersurface thereof, said depressions adapted to receive an inwardlyextending lip provided on the housing.
 80. A drill attachment as claimedin claim 79, wherein interaction of the circumferential depressions andthe lip acts to retain the collar in the desired position such that thecollar cannot inadvertently be pushed into or pulled from the housingduring a drilling operation.
 81. A drill attachment as claimed in claim73, wherein the collar includes a plurality of longitudinal ribscircumferentially distributed about the outer surface of the collar,said ribs defining a number of depressions adapted to receive aninwardly extending lip provided on the housing.